1. Field of the Invention
The present invention relates to processes and systems for obtaining flow rates of fluids produced from a subterranean well without well intervention, and more particularly, to processes and systems for obtaining flow rates of fluids produced from a substantially horizontal subterranean well without well intervention.
2. Description of Related Art
In the production of fluid from subterranean environs, a well bore may be drilled so as to penetrate one or more subterranean environs. The well bore may be drilled into or through the one or more subterranean environs of interest in a generally vertical, deviated or horizontal orientation. The well is typically completed by positioning casing which may be made up of tubular joints into the well bore and securing the casing therein by any suitable means, such as cement positioned between the casing and the walls of the well bore. Thereafter, the well may be completed in a typical manner by conveying a perforating gun or other means of penetrating casing to a position that is adjacent the subterranean environs of interest and detonating explosive charges so as to perforate both the casing and the subterranean environs. In this manner, fluid communication may be established between the subterranean environs and the interior of the casing to permit the flow of fluid from the subterranean environs into the well. Alternatively, the well may be completed as an “open hole”, meaning that casing is installed in the well bore but terminates above the subterranean environs of interest. The well may be subsequently equipped with production tubing and conventional associated equipment so as to produce fluid from the subterranean environs of interest to the surface. The casing and/or tubing may also be used to inject fluid into the well to assist in production of fluid therefrom or into the subterranean environs to assist in extracting fluid therefrom.
Further, it is often desirable to stimulate the subterranean environs of interest to enhance production of fluids, such as hydrocarbons, therefrom by pumping fluid under pressure into the well and the surrounding subterranean environs of interest to stimulate the environs, for example by inducing hydraulic fracturing thereof. Thereafter, fluid can be produced from the subterranean environs of interest, into the well bore and through the production tubing and/or casing string to the surface of the earth. Where it is desired to stimulate, for example fracture, the subterranean environs of interest at multiple, spaced apart locations along a well bore penetrating the environs, fluid is pumped into a particular location adjacent the subterranean environs of interest while means, such as a flapper valve(s) or gelled fluids placed in the open hole, is employed to isolate the remaining locations. Once fluid is pumped under pressure from the surface into the well and the particular location, means are actuated to isolate the next location and fluid is pumped under pressure from the surface into the well and the subterranean environs adjacent the isolated location so as to hydraulically fracture the same. In this manner, all of the subterranean environs adjacent to the multiple, spaced apart locations can be hydraulically fractured. Conventional systems and associated methodology that are used to stimulate subterranean environs in this manner include casing conveyed perforating systems, ball drop systems, and perforate and plug systems.
Once communication is established between the subterranean environs of interest and a well bore, it may often be desirable to determine the nature of production from the subterranean environs, especially when communication is established at multiple locations along the well bore. Production logs may be run to determine the productivity or injectivity of the subterranean environs. Conventional production logging systems require access to the well bore at appropriate depths along the subterranean environs of interest to determine flow rates of fluids produced from such environs by a myriad of means involving direct measurement. Measurement tools are conveyed on wireline or pipe requiring an appropriate rig and the time and expense associated therewith. Flow regimes may be significantly disturbed while operating conventional production logging equipment. As conveyance of such measurement tools in highly deviated or horizontal wells may often be difficult and expensive, e.g. requiring production from the well to be shut in or stopped and sand to be removed by circulating fluid through the well bore, production logs are not run in the vast majority of deviated the vast majority of deviated wells. Instead only total fluid returns are measured at the surface well head.